Vomiting is the forceful ejection of the contents (such as food or fluids) of the stomach and upper small in testine. It is normally preceded by excessive drooling, retching, and forceful contractions of the abdominal muscles and the diaphragm. Vomiting can be caused by digestive system disease, kidney or liver failure, pancreatitis, or nervous system disorders (including ingestion of poisons).

Managing Hairballs in Cats
As cats groom themselves they swallow some of the loose hair from their coat. Hair cannot be digested and tends to stick together in the stomach, where it forms into a lump or hairball (also called a trichobezoar). Often, cats will vomit up the hairball. In some cases, however, it remains in the stomach for a long time and hardens into a dense mass. This can irritate the stomach or even block the digestive tract. Longhaired breeds are at greater risk. You can limit the amount of hair your cat swallows and help prevent hairballs from forming by frequently brushing your cat to remove loose fur. If necessary, medications such as mineral oil can be given to help cats pass hair through the digestive tract. Some commercial cat diets and treats are also formulated to help prevent formation of hairballs. In severe cases, surgery may be required to remove the hairball.

Vomiting differs from regurgitation, which is a passive motion. With regurgitation, the expelled food and fluid tends to be undigested and may have a cylindrical shape reflecting the shape of the esophagus. Coughing or difficulty breathing are more often associated with regurgitation than with vomiting.

Short-term or occasional vomiting is generally not associated with other abnormalities. Longterm vomiting may be associated with weakness, lethargy, weight loss, dehydration, and electrolyte (salt) imbalance. Whenever possible, control of vomiting is achieved by identifying and eliminating the cause while allowing the digestive system time to recover.

Short-term or Occasional Vomiting

When a cat has been vomiting for only a short time (less than 3 to 4 days) and no other signs of disease are present, treatment to relieve signs may be all that is needed. Generally, the treatment for short-term vomiting requires withholding food and limiting access to water for 24 hours. Cats with kidney or heart disease may require a hospital stay with intravenous fluid treatment during this time. If the vomiting has stopped after 24 hours, the cat may be offered small amounts of water. If no further vomiting occurs, feeding can usually be resumed slowly.

Longterm or Severe Vomiting

Longterm vomiting, vomiting that occurs more often than once or twice daily, and vomiting accompanied by blood, abdominal pain, depression, dehydration, weakness, fever, or other adverse signs requires a detailed examination by your veterinarian. This may include blood and urine tests as well as abdominal x-rays. In many cases, endoscopic evaluation and biopsy of the stomach and small intestine are the only tests that can determine the cause of the vomiting.

A cat with longterm vomiting may need to be treated for conditions such as dehydration, salt imbalances, and acid-base disorders that have developed. Drugs to control vomiting can be prescribed for animals with persistent vomiting, dehydration, and weakness.

Last full review/revision July 2011 by Dana G. Allen, DVM, MSc, DACVIM; Sharon Campbell, DVM, MS, DACVIM; Ben H. Colmery, DVM, DAVDC; James G. Fox, DVM, MS, DACLAM; Carlton L. Gyles, DVM, PhD, FCAHS; Walter Ingwersen, DVM, DVSc, DACVIM; Lisa E. Moore, DVM, DACVIM; Sofie Muylle, DVM, PhD; Sharon Patton, MS, PhD; Andrew S. Peregrine, BVMS, PhD, DVM, DEVPC; Stanley I. Rubin, DVM, MS, DACVIM; H. Carolien Rutgers, DVM, MS, DACVIM, DECVIM-CA, DSAM, MRCVS; Jörg M. Steiner, DrMedVet, PhD, DACVIM, DECVIM-CA; Thomas W. Swerczek, DVM, PhD